Catz might not be a household name, but she's one of Ellison's most trusted executives at Oracle. It's why Ellison once famously said, "If I dropped dead tomorrow, Safra Catz would be CEO of Oracle."

Ellison is known for being a tough and demanding boss. Many executives have come and gone during his 37-year reign. The fact that Catz has been an Oracle executive for 15 years, earning the trust of Ellison along the way, says a lot about her influence within the company.

Shortly after joining Oracle in 1999, Catz quickly expanded her role, becoming executive VP within seven months and a board member by 2001. In one of those years, a big meeting took place at Oracle's headquarters with Ellison and 30 other executives. After a while, Ellison was clearly getting distracted, and he started to leave the room saying he had a prior engagement.

That's when Catz stopped him. Lashinsky writes:

Catz immediately sprang from her chair. "Safra grabbed him by the arm," recalls one participant, "and said, 'Larry, you can't leave. This is important. And I know you have the time for this.' And he sat back down. No one else at Oracle could do that."

Catz rarely speaks to the press, and still remains largely enigmatic to a lot of people outside of Oracle. But now that Ellison has stepped down, Catz will no longer be able to hide behind the shades of a charismatic leader. And stories like this only tell Catz is more than capable of keeping Oracle humming even after Ellison is gone.